This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1hcb
From Proteopedia
| Line 1: | Line 1: | ||
| - | [[Image:1hcb.gif|left|200px]] | + | [[Image:1hcb.gif|left|200px]] |
| - | + | ||
| - | '''ENZYME-SUBSTRATE INTERACTIONS: STRUCTURE OF HUMAN CARBONIC ANHYDRASE I COMPLEXED WITH BICARBONATE''' | + | {{Structure |
| + | |PDB= 1hcb |SIZE=350|CAPTION= <scene name='initialview01'>1hcb</scene>, resolution 1.6Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene> and <scene name='pdbligand=BCT:BICARBONATE ION'>BCT</scene> | ||
| + | |ACTIVITY= [http://en.wikipedia.org/wiki/Carbonate_dehydratase Carbonate dehydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.1 4.2.1.1] | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''ENZYME-SUBSTRATE INTERACTIONS: STRUCTURE OF HUMAN CARBONIC ANHYDRASE I COMPLEXED WITH BICARBONATE''' | ||
| + | |||
==Overview== | ==Overview== | ||
| Line 7: | Line 16: | ||
==About this Structure== | ==About this Structure== | ||
| - | 1HCB is a [ | + | 1HCB is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HCB OCA]. |
==Reference== | ==Reference== | ||
| - | Enzyme-substrate interactions. Structure of human carbonic anhydrase I complexed with bicarbonate., Kumar V, Kannan KK, J Mol Biol. 1994 Aug 12;241(2):226-32. PMID:[http:// | + | Enzyme-substrate interactions. Structure of human carbonic anhydrase I complexed with bicarbonate., Kumar V, Kannan KK, J Mol Biol. 1994 Aug 12;241(2):226-32. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8057362 8057362] |
[[Category: Carbonate dehydratase]] | [[Category: Carbonate dehydratase]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
| Line 20: | Line 29: | ||
[[Category: lyase(oxo-acid)]] | [[Category: lyase(oxo-acid)]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:35:22 2008'' |
Revision as of 09:35, 20 March 2008
| |||||||
| , resolution 1.6Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Activity: | Carbonate dehydratase, with EC number 4.2.1.1 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
ENZYME-SUBSTRATE INTERACTIONS: STRUCTURE OF HUMAN CARBONIC ANHYDRASE I COMPLEXED WITH BICARBONATE
Overview
The structure of HCAI-HCO3- complex has been refined with 10-1.6A X-ray diffraction data to an R-value of 17.7%. The structure reveals monodentate binding of the HCO3- anion at an apical tetrahedral position to the zinc ion. The binding mode and interactions of HCO3- in HCAI differ from that in HCAII. The activity linked H2O/OH- group in the free HCAI is replaced by the hydroxyl group of the bicarbonate anion. This result rules out the rearrangement of the bound HCO3- advocated earlier to explain the microscopic reversibility of the catalysed reaction. From the geometry of the H-bonds between Glu106-Thr199 pair and Glu117-His119 couple, the glutamic acids are expected to be ionized and accept H-bonds from their partners. The product-inhibiton by HCO3- anion is explained on the basis of proton localization on His119 in the Glu117-His119 couple. These results are consistent with the hypothesis that Glu117-His119 tunes the ionicity of the Zn2+ and the binding strength of HCO3- anion. A pi hydrogen bond is observed between a water and phenyl ring of the Tyr114 residue.
About this Structure
1HCB is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Enzyme-substrate interactions. Structure of human carbonic anhydrase I complexed with bicarbonate., Kumar V, Kannan KK, J Mol Biol. 1994 Aug 12;241(2):226-32. PMID:8057362
Page seeded by OCA on Thu Mar 20 11:35:22 2008
